3D flower-structured graphene from CO 2 for supercapacitors with ultrahigh areal capacitance at high current density

3D cauliflower-fungus-like graphene (CFG) with hierarchical mesoporous-structure synthesized directly from CO 2 exhibited an ultrahigh areal capacitance of 1.16 F cm −2 at a high current density and reached a high efficient-mass-loading of 11.16 mg cm −2 . This solves a critical issue of sacrificing mass capacitance with increasing mass loading.